Hot deformation and processing maps of a Fe–Al intermetallic alloy

• The deformation of Fe-Al alloys under hot compression conditions was characterized.
• Processing maps were calculated to evaluate the efficiency of the hot working.
• Optimum hot working conditions domain occurs above 800 °C at < 10− 1–10−2 s−1 for = 0.6.
• Materials undergoes dynamic recrystallization to produce a fine-grained structure.
• High efficiency of power dissipation mean possibility of the superplastic deformation.

Iron aluminide alloys are advanced structural materials with promising properties for elevated temperature applications in a hostile environment. They offer a combination of unique properties such as corrosion and wear resistance, high temperature strength, lower density and cost advantage over the Fe–Cr or Fe–Cr–Ni stainless steels. In our work, the deformation behavior of a Fe–16Al–5Cr–1Mo–0.1Zr (at.%) alloy (hereafter known as Fe–16Al) under hot compression conditions was characterized in the temperature range 600–1100 °C and strain rate range 10−3–102 s−1.Processing maps were calculated to evaluate the efficiency of the hot working and to recognize the instability regions of the flow behavior. The isothermal, constant-strain rate compression tests were carried out on a Gleeble 3800 testing system. The flow stress was found to be strongly dependent on temperature and strain rate. At higher strain rates or lower temperatures, the Fe–16Al alloy exhibited a flow-softening type of stress–strain curve, while at lower strain rates or at higher temperatures, the flow curves were of a steady-state type. The tested alloy possesses the optimum hot working condition domain above 750 °C at 10− 1–10−2 s−1 for ε = 0.6, since the material undergoes dynamic recrystallization to produce a fine-grained structure (deq ≈ 20–50 μm) with a high fraction of high angle boundaries (~ 40%) and the peak efficiencies (η = 56% at 750 °C and 10−3 s−1).These results have been related to the earlier reported results, achieved for two intermetallic alloys: Fe3Al (Fe–28Al–5Cr–0.08Zr–0.04B at.%) and FeAl (Fe–36Al–0.22Mo–0.05Zr–0.01B at.%).

Determination of parameters of hot working with the use of processing map approach.Figure optionsDownload as PowerPoint slide